For the majority of "Room," Cohen confined his camera to a dingy suburban garden shed, where a woman and her 5-year-old son, played by Brie Larson and Jacob Tremblay, are held captive.

How did you make two films shot on the same camera look so different?

We used different lenses. So on "The Danish Girl," we used Arri Master Primes. And on "Room," we used Panavision Primos. And they definitely have a certain look to them. The Primos are a little bit contrastier than the Master Primes. The Primos and using Kino Flos, which is more akin to fluorescent lighting, gave "Room" a certain texture, a certain look.

What's the look of the Master Primes?

One of the things with [director Tom Hooper] on "The Danish Girl," he was very much after a very, very shallow depth of field. So [with] the Master Primes, the aperture, which helps dictate how shallow the focus is, goes to 1.3. So what it means is essentially there's only one point of focus, and you're choosing where you're guiding the audience a little bit about what to look at.

While filming intimate scenes, such as Eddie observing his naked body in a mirror, how did you remain unobtrusive?

That was filmed on a location in London, which is Wilton's Music Hall, which has these amazing distressed textured walls. You very much have to be mindful that you don't want to clutter the world with lighting stands and equipment, because it can easily just take away from the moment. So in that instance, we did really simple lighting to make Eddie look amazing. It wasn't much more than a few hanging light bulbs, and a little soft light that he walks into. It's important that — not that they would be intimidated — but you really just give the actors a lot of space, and especially a scene like that, or the scene when Eddie goes to the Parisian striptease.

What inspired the film's look?

There's a Danish painter called Vilhelm Hammershøi. And that was where all the conversations began, just because if you look at his paintings, he's got a very austere, quite hardcore approach to where he puts people in the frame, the colors of the paint, how he uses shadow. It's so full of ideas. We stole liberally.

So on "Room," were you filming in a real garden shed?

We built a shed on a stage. Essentially, the reason is for the lighting: to have the flexibility that we could completely control it so there'd be no bad weather days. Essentially, everything you shouldn't do as a filmmaker, we started doing, which is find smaller space and then try to put two actors in it, two cameras. But what hopefully comes across in the film is that, in setting ourselves those restrictions, you really get the tension and the claustrophobia.

If we wanted to take a wall off, we could. But what we ended up discovering was that keeping it as a solid four-walled shed just gave it a bit more atmosphere, if you like. What we did do is you could take bits of the wall out, so you could put the camera lens on the plane of the wall, but you could actually have the body of the camera outside the shed. And we could take the floor out, if you wanted to get very low shots. In the room, we very much wanted to tell the story from [the boy's] point of view.

How did it feel to shoot the final scene of the room from the outside looking in?

We built that shed in that garden pretty much as it was on set. And then as soon as you take the furniture out, the place just shrinks and shrinks and shrinks. When you revisit it for the end sequence, you think, "How the hell did we shoot in this room for five weeks? It's this small!" It was a really amazing experience.